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Mixing Nutrients for your Flex Acre (Part 3 of 5)

Part 3 of 5: How to read your PPM and dose Nutrient A & B to the target for your crop

After Cleaning your Disc Filter (Part 2 of 5), water is moving cleanly through your Flex Acre and you can dose your Tank for the week. Follow the instructions in this article to read your current nutrient level and bring it to the target for the age of your crop. Follow the steps in Keeping your Flex Acre Clean before you begin.

Gather Tools:

  • TDS Meter
  • Nutrient A
  • Nutrient B
  • 5-Gallon Bucket
  • Mixing Tool
  • Water Level Tool
  • Hot Water

Step 1: Confirm your Water Level

  1. Look into your Tank and confirm the water sits at approximately 3 inches below the top.
  2. Check that the level reads between the MIN and MAX lines on the Water Level Tool.
  3. Top off your Tank with water before you dose if the level sits low.

A full Flex Acre Tank holds roughly 80 gallons, and every dose below is measured against that volume. Letting the water fall below the top of your Primary Pump voids your warranty.

Step 2: Take your Initial Reading

  1. Take an initial nutrient reading with your TDS Meter.
  2. Record the reading before you mix anything.

Your initial reading tells you how much feed your crop has pulled out of the Tank since the last dose. The targets below are stated in EC, and your weekly log records both your PPM and your EC.

Step 3: Set your Target for Seedlings Planted 1 to 2 Weeks Ago

Seedlings planted 1 to 2 weeks ago follow the target below. Seedlings planted 3 to 4 weeks ago are covered under the next heading.

  1. Set your target at an EC of 1.0 to 1.2 for seedlings planted 1 to 2 weeks ago.
  2. Compare your initial reading against that range.

Step 3: Set your Target for Seedlings Planted 3 to 4 Weeks Ago

Seedlings planted 3 to 4 weeks ago follow the target below. Seedlings planted 1 to 2 weeks ago are covered under the heading above.

  1. Set your target at an EC of 1.2 to 1.4 for seedlings planted 3 to 4 weeks ago.
  2. Compare your initial reading against that range.

Both ranges are set by the number of weeks since planting, so read the planting date off the labeling tape on your tray.

Step 4: Dissolve and Pour Nutrient A

  1. Fill a 5-gallon bucket with hot water.
  2. Dissolve Nutrient A in the bucket first.
  3. Pour the bucket into the pump side of your Tank.
  4. Stir your Tank with the mixing tool.

Nutrient A and Nutrient B go into your Tank at a 1:1 ratio, one part at a time. Use only the nutrients supplied by Fork Farms, as dosing with another product voids your warranty.

CAUTION: NEVER MIX NUTRIENT A AND NUTRIENT B TOGETHER IN THE BUCKET. DISSOLVE AND POUR ONE PART AT A TIME.

Step 5: Dissolve and Pour Nutrient B

  1. Fill your 5-gallon bucket with hot water.
  2. Dissolve Nutrient B in the bucket.
  3. Pour the bucket into the pump side of your Tank.
  4. Stir your Tank with the mixing tool.

Step 6: Stabilize and Re-Check

  1. Allow the pump to cycle for at minimum 1 hour before you re-check your PPM.
  2. Take a reading on the pump side of your Tank.
  3. Take a second reading on the far side of your Tank.
  4. Confirm both readings are consistent.
  5. Repeat Steps 4 through 6 until your target PPM or EC is reached.

An hour of cycling carries the concentrate up to your Drip Lines, down the wall and back into your Tank, which is what brings both sides to the same number. A reading taken before the hour is up reads the pump side only. Every repeat dose earns its own hour of cycling and its own two readings before you add anything else. If your readings land on target but your plants still show yellowing leaves, stunted growth or purple discoloration, see Correcting Nutrient Deficiencies.

Nutrients come third in the weekly circuit because the hour of stabilization runs without you. Spend that hour on Wiping Light Bars & Pruning your Plants (Part 5 of 5), then come back and read your pH.

Your Tank is dosed and stabilizing—well done! Continue to Adjusting your pH after Dosing (Part 4 of 5) for next steps.